56S 


SB    314    135 


EXCHANGE 


The   Conductivities,  Temperature  Coeffi- 
cients of  Conductivity  and  Dissociation  of 
Certain  Electrolytes  from  0°  to  35°, 
and  of   Certain   Other  Elec- 
trolytes from  35°  to  65°. 


DISSERTATION. 


SUBMITTED  TO  THE  BOARD  OF  UNIVERSITY  STUDIES  OF  THE  JOHNS 
HOPKINS  UNIVERSITY  IN  CONFORMITY  WITH  THE    REQUIRE- 
MENTS FOR  THE  DEGREE  OF  DOCTOR  OF  PHILOSOPHY. 


BY 
HENRY  HALLOCK  HOSFORD, 

J9U 


EASTON,  PA.: 

KSCHENBACH  PRINTING  COMPANY 
I9II. 


The   Conductivities,  1  emperature  Coeffi- 
cients of  Conductivity  and  Dissociation  of 
Certain  Electrolytes  from  0°  to  35°, 
and  of   Certain   Other  Elec- 
trolytes from  35°  to  65°. 


DISSERTATION. 


SUBMITTED  TO  THE  BOARD  OF  UNIVERSITY  STUDIES  OF  THE  JOHNS 
HOPKINS  UNIVERSITY  IN  CONFORMITY  WITH  THE    REQUIRE- 
MENTS FOR  THE  DEGREE  OF  DOCTOR  OF  PHILOSOPHY. 


BY 


HENRY  HALLOCK  HOSFORD. 

H 
J9JJ 


EASTON,  PA.: 

ESCHENBACH  PRINTING  COMPANY 
1911. 


5(0 


ACKNOWLEDGMENT. 

The  author  wishes  to  offer  his  sincere  thanks  for  instruction 
in  lecture  room  and  laboratory  to  President  Remsen,  Pro- 
fessors H.  N.  Morse,  H.  C.  Jones,  Renouf,  Bliss,  Associate  Pro- 
fessor Acree  and  Dr.  Pfund. 

This  investigation  was  undertaken  at  the  suggestion  of  Pro- 
fessor H.  C.  Jones  and  was  carried  out  under  his  supervision. 


251847 


CONTENTS. 

Acknowledgment 3 

Historical  Review 5 

Purpose  of  This  Investigation 6 

Preparation  of  Material 6 

Apparatus  and  Method 7 

Experimental  Results 9 

Salts  Studied  from  o°  to  35 ° 9 

Ammonium  Aluminium  Sulphate 9 

Ammonium  Chromium  Sulphate  (Violet  Variety) 10 

Ammonium  Chromium  Sulphate  (Green  Variety) 10 

Ammonium  Copper  Sulphate 1 1 

Sodium  Ferrocyanide 12 

Potassium  Sodium  Sulphate \2 

Potassium  Aluminium  Sulphate 13 

Potassium  Nickel  Sulphate 14 

Potassium  Chromium  Sulphate  (Violet  Variety) 15 

Potassium  Chromium  Sulphate  (Green  Variety) J 15 

Calcium  Formate 16 

Calcium  Chromate 17 

Zinc  Nitrate 17 

Zinc  Acetate 18 

Lead  Acetate 19 

Salts  Studied  from  35°  to  65° 20 

Ammonium  Aluminium  Sulphate 20 

Disodium  Phosphate 21 

Sodium  Tetraborate 21 

Potassium  Aluminium  Sulphate 22 

Potassium  Sulphocyanate 22 

Monopotassium  Phosphate 23 

Potassium  Acetate 23 

Calcium  Chloride 24 

Magnesium  Chloride 24 

Manganese  Sulphate 25 

Ferric  Chloride . '.^. /*.•,  ....:,./.;, ;  ..£.<;. .  • 26 

Chromium  Sulpha te  "(Green  Variety;.'//. 26 

Nickel  Nitrate.?,.  .;.;.  ..?.,.•  j...*.  •«.;.  ?.  .  ? .  .*.  .'.*.' 27 

Nickel  Sulphate ,° .:/.  \  .'•! ; : .  {  /.: .  ( . .  1  /A .«../ 27 

Cobalt  Sulphate 28 

Copper  Sulphate 28 

Discussion  of  Results 29 

Summary 41 

Biography 43 


THE     CONDUCTIVITIES,     TEMPERATURE     COEFFI- 
CIENTS   OF    CONDUCTIVITY   AND    DISSOCIA- 
TION   OF    CERTAIN    ELECTROLYTES 

HISTORICAL  REVIEW 

Volta,  at  the  end  of  the  eighteenth  century,  distinguished 
two  classes  of  conductors  of  the  then  recently  discovered 
galvanism.  The  first  class  comprised  those  substances,  such 
as  metals,  which  conduct  without  chemical  change;  while 
conductors  of  the  second  class  were  decomposed  by  the  passage 
of  the  current.  A  few  years  later,  by  electrolyzing  conduc- 
tors of  the  second  class,  Davy  isolated  the  previously  unknown 
metals  of  the  alkalies  and  the  alkaline  earths.  Faraday,1  in 
1832,  published  his  laws  showing  the  relation  between  the 
amount  of  electricity  passed  through  the  electrolyte  and  the 
amount  of  the  electrolyte  decomposed. 

Measurements  of  the  resistance  of  solutions  of  electrolytes 
were  soon  made  by  many  investigators.  Of  these  early  re- 
searches those  of  Hankel,2  Becquerel,3  Horsford,4  Wiedeman,5 
Becker,8  and  Beetz7  may  be  especially  noted.  Brief  dis- 
cussions of  these  and  other  investigations  can  be  found  in 
Wiedemann's  book.8 

The  earlier  methods  were  very  imperfect.  The  continuous 
current  was  used,  causing  polarization  of  the  electrodes,  ex- 
cept in  some  special  cases,  as  when  the  metal  of  the  salt  was 
used  for  the  electrodes.  The  standard  method  now  used 
practically  eliminates  polarization  by  using  the  alternating 
current.  This  method  was  first  developed  and  used  by  Kohl- 
rausch  and  his  coworkers  in  a  series  of  researches9  that  were 
far  more  comprehensive  than  any  preceding  investigations. 

1  Exp.  Researches,  III,  Ser.  No.  373  (1832). 

2  Pogg.  Ann.,  69,  255  (1846). 

3  Ann.  chim.  phys.,  [3]  17,  267  (1846). 

4  Pogg.  Ann.,  70,  238  (1847). 

5  Ibid.,  99,  225  (1856). 

e  Ann.  Chem.  (Liebig),  73,  1  (1850);  75,  94  (1851). 
i  Pogg.  Ann.,  117,  1  (1862). 

8G.  Wiedemann:   Die  Lehre  von  der  Elektricitat,  Band  I    (Braunschweig,    1882). 
9  For  brief  discussions  and  references  to  original  publications  see  Wiedemann: 
Loc.  cit. 


The  dissociation  theory  of  Arrhenius1  imparted  new  life  to 
conductivity  measurements  of  electrolytes  as  affording  a 
basis  for  the  accurate  determination  of  the  degree  of  ioniza- 
tion. 

Following  Kohlrausch,  many  investigations  in  this  field 
have  been  carried  out,  but  in  most  cases  with  some  special 
object  in  view  which  has  limited  the  scope  of  the  work.  The 
researches  were  concerned  with  a  few  substances  only,  or  were 
confined  to  a  narrow  range  of  temperature  and  concentration. 

PURPOSE  OF  THIS  INVESTIGATION 

It  has  seemed  desirable  to  secure  conductivity  data  relative 
to  all  the  substances  in  more  common  use  by  the  chemist, 
and  under  the  conditions  of  temperature  and  dilution  at  which 
they  are  usually  employed  in  chemical  work.  With  this  end 
in  view,  a  systematic  study  of  the  electrical  conductivities  and 
allied  relations  of  acids,  bases  and  salts  in  aqueous  as  well  as 
in  nonaqueous  solutions,  and  at  various  temperatures  and 
concentrations,  has  been  in  progress  in  this  laboratory  for  ten 
years.  Six  papers1  dealing  solely  with  aqueous  solutions 
have  been  published  and  other  investigations  are  in  progress. 

The  work  herein  described  was  undertaken  as  a  continua- 
tion of  that  already  carried  out  on  the  general  problem.  It 
includes  the  determination  of  the  electrical  conductivities, 
temperature  coefficients  of  conductivity  and  percentage  dis- 
sociation of  a  number  of  inorganic  salts  at  dilutions  ranging 
from  N/2  to  N/4O96.  Some  of  the  measurements  were  made 
over  a  range  of  temperature  from  o°  to  35°,  and  a  part  from 
35°  to  65°. 

PREPARATION  OF  MATERIAL 

The  salts  used  were  the  purest  available.  In  nearly  all 
cases  Kahlbaum's  chemicals  were  employed.  These  were  re- 
crystallized  from  one  to  five  times,  the  final  crystallizations 
in  all  cases  being  made  from  water  of  special  purity  or  so-called 
"conductivity  water."  Any  deviations  from  this  general 

»  Z.  physik.  Chem.,  1,  631  (1881).     Scientific  Memoirs,  Series  IV,  p.  47. 

2  Jones  and  Douglas:  Am.  Chem.  J.,  26,  428  (1901).  Jones  and  West:  Ibid.,  34, 
357  (1905).  Jones  and  Jacobson:  Ibid.,  40,  355  (1908).  Clover  and  Jones:  Ibid.,  43, 
187  (1910).  White  and  Jones:  Ibid.,  44,  159  (1910).  West  and  Jones;  Ibid.,  44, 
508  (1910). 


procedure   are   stated   in   connection  with   the   experimental 
data  under  each  salt. 

The  water  used  in  making  up  the  solutions  was  prepared 
by  a  modification  of  the  method  of  Jones  and  Mackay,1  i.  e.,  by 
subjecting  the  distilled  water  of  the  laboratory  to  three  ad- 
ditional distillations:  first  in  the  presence  of  potassium  di- 
chromate  and  sulphuric  acid  to  oxidize  organic  matter  and  re- 
tain ammonia,  and  twice  with  barium  hydroxide  to  absorb 
carbon  dioxide.  The  conductivity  of  such  water  varies  from  , 
i.o  to  1.5  X  io~".  The  correction  of  the  molecular  conduc- 
tivity due  to  this  cause  is  negligible  in  the  greater  concentra- 
tions, but  was  calculated  and  applied  to  the  conductivity 
values  obtained  for  the  dilute  solutions. 

APPARATUS  AND  METHOD 

The  Kohlrausch  method  was  used  in  this  investigation. 
In  the  work  from  35°  to  65°  a  slide- wire  bridge  of  the  usual 
type  was  employed,  while  measurements  from  o°  to  35°  were 
made  by  means  of  an  improved  slide-wire  bridge  made  by 
Leeds  and  Northrup,  the  wire  being  about  five  meters  long. 
The  bridges  and  resistance  coils  were  standardized  by  Leeds 
and  Northrup  and  also  by  means  of  resistances  which  had  been 
corrected  by  the  U.  S.  Bureau  of  Standards. 

The  conductivity  cells  were  of  the  type  used  and  described 
by  Clover  and  Jones2  and  Jones  and  West.3  The  constants 
of  these  cells  were  determined  at  short  intervals.  In  connec- 
tion with  the  work  from  o°  to  35°  the  following  method  of 
determining  the  constants  was  employed.  A  0.02  N  solution 
of  carefully  purified  potassium  chloride  was  prepared,  using 
water  of  special  purity.  The  molecular  conductivity  of  this 
solution  at  25°  was  assumed  to  have  Kohlrausch's  value  of 
129.7,  an(i  this  solution  was  used  to  determine  the  constants 
of  the  cells  designed  for  concentrated  solutions.  A  0.002  N 
solution  of  potassium  chloride  was  also  prepared,  and  its 
molecular  conductivity  found  by  means  of  a  cell  whose  con- 
stant had  been  determined  as  explained  above.  This  0.002  N 

i  Z.  physik.  Chem.,  14,  317  (1894).     Am.  Chem.  J.,  If,  91  (1897). 
a  Am.  Chem.  J.,  43,  192  (1910). 
4,  510  (1910). 


8 

solution  was  then  used  in  finding  the  constants  of  the  cells 
intended  for  the  more  dilute  solutions. 

In  connection  with  the  work  from  o°  to  35°,  a  slightly  differ- 
ent plan  was  adopted.  Solutions  of  potassium  chloride  of 
0.02  N  and  0.002  N  concentration  were  prepared  and  used  as  de- 
scribed; but  a  fixed  value  of  136.5  at  25°  was  taken  for  the 
molecular  conductivity  of  the  0.002  N  solution.  This  value  is 
based  on  repeated  measurements  made  in  this  laboratory. 

So  far  as  possible  the  initial  or  mother  solution  of  each  salt 
was  prepared  by  direct  weighing  of  the  properly  purified  sub- 
stance. If  this  was  impracticable  a  mother  solution  of  con- 
venient strength  was  made  up  and  standardized  by  analysis. 
From  the  mother  solution  the  various  concentrations  were 
prepared  by  dilution.  In  the  case  of  the  work  from  o°  to  35°, 
solutions  were  made  up  at  20°  and  were  used  without  correc- 
tions at  the  various  temperatures  at  which  measurements 
were  made,  the  correction  being  less  than  the  known  experi- 
mental error.  When  working  from  35°  to  65°  solutions  were 
prepared  at  50°,  and  a  factor  was  employed  in  the  reduction 
of  all  measurements  made  at  35°  and  65°  to  correct  for  the 
change  in  concentration  due  to  change  in  volume.  The  cor- 
rection factor  for  the  molecular  conductivity  of  solutions 
made  at  50°  and  used  at  35°  is  0.994;  f°r  those  made  at  50° 
and  used  at  65°  the  value  is  i  .0076.  The  burettes  and  meas- 
uring flasks  used  in  making  up  solutions  were  carefully  cali- 
brated for  the  temperature  at  which  they  were  to  be  used. 

For  the  work  at  o°  an  ice  bath  was  employed  in  which  the 
cells  were  supported  so  as  to  be  immersed  as  deeply  as  possi- 
ble in  the  crushed  ice  and  water.  A  shallow  vessel  filled  with 
ice  and  water  covered  the  ice  baths  when  in  use.  Connections 
were  made  through  openings  closed  with  perforated  stoppers 
carrying  the  conducting  wires.  The  baths  for  higher  tem- 
peratures were  properly  sheathed  with  asbestos  cement,  and 
in  the  case  of  the  50°  and  65°  baths  efficient  covers  were  pro- 
vided to  retain  the  heat.  Hot-air  engines  were  used  to  stir 
the  baths.  It  was  found  easy  to  keep  the  temperature  of  the 
baths  constant  to  within  o°.02  or  o°.o3  by  hand  regulation, 
and  this  method  was  adopted. 


From  two  to  four  independent  measurements  of  the  con- 
ductivity were  made  for  each  concentration  at  each  tempera- 
ture. If  there  was  not  close  agreement  in  the  results,  or  if  any 
abnormally  large  errors  were  suspected,  the  measurements 
were  repeated.  So  far  as  possible  my  results  were  compared 
with  those  obtained  by  other  workers.  In  most  cases  there  is 
reasonable  agreement.  When  wide  discrepancies  appeared 
my  work  was  duplicated. 

Concentrations  are  indicated  under  the  heading  V,  or 
the  number  of  liters  which  would  contain  one  gram- 
molecular  weight  of  the  salt.  Molecular  conductivities  are 
expressed  in  Siemens'  units.  The  temperature  coefficients 
and  dissociation  were  calculated  in  the  usual  way.  On  ac- 
count of  hydrolysis  or  other  causes,  the  maximum  value  of 
the  molecular  conductivity  (p^)  was  not  found  for  certain 
salts  at  the  greatest  dilution  worked  with.  In  such  cases  the 
dissociation  was  not  calculated. 

Ammonium  Aluminium  Sulphate,  NH4Al(SO4)2.i2H2O 
The    mother    solution    was    standardized    by    determining 
aluminium  as  aluminium  oxide. 

Table  I. — Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35* 

8 

8o.o 

II0.9 

H3  -I 

168.8 

32 

IO2  .5 

I43-I 

185-5 

22O-4 

128 

I30.I 

182.7 

238.8 

284.8 

512 

l62  .2 

230.9 

304-5 

365-9 

1024 

iSl.O 

257-5 

342-4 

4I5-i 

2048 

201.8 

288.2 

386.4 

485.8 

4096 

224.  I 

322.8 

437-6 

540-3 

Table  II.  —  Temperature  Coefficients 

0°-12°.5  12°.  5-25°  25°-35° 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

8 

2.47 

3-09 

2.58 

2-33 

2-57 

I.  80 

32 

3-25 

3-17 

3-39 

2-37 

3-49 

1.88 

128 

4.21 

3-24 

4-49 

2  .46 

4.60 

i-93 

512 

5-50 

3-39 

5-89 

2-55 

6.  14 

2  .02 

1024 

6.12 

3-38 

6.79 

2.64 

7.27 

2  .  12 

2048 

6.91 

3-42 

7.86 

2  -  73 

9-94 

2-57 

4096 

7.90 

3-53 

8.38 

2  .60 

10.27 

2-35 

10 

Ammonium  Chromium  Sulphate  (Violet  Variety), 
NH4Cr($O4)2.i2H20 

The  mother  solution  was  standardized  in  the  same  manner 
as  in  the  case  of  the  potassium  salt. 

Table  HI. — Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

8 

77-5 

106.4 

137-3 

162.7 

16 

88.9 

123.2 

159-5 

188.3 

32 

100.8 

140.3 

182.2 

216.0 

128 

129-5 

183.0 

240.2 

285.9 

512 

165  5 

238.0 

321.0 

385.9 

1024 

187.0 

272.0 

372.0 

455-7 

2048 

211  .9 

310.7 

428.5 

530-0 

4096 

240.7 

355-6 

492.2 

617.0 

Table  IV. — Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35< 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

8 

2.31 

2.98 

2.47 

2.32 

2-54 

1-85 

16 

2.74 

3.08 

2  .90 

2-35 

2.88 

1.81 

32 

3-16 

3-H 

3-35 

2-39 

3.38 

1.86 

128 

4.28 

3-31 

4-57 

2.5° 

4-57 

1.90 

512 

5.80 

3-51 

6.64 

2.79 

6.49 

2  .02 

1024 

6.80 

3-64 

8.00 

2-94 

8-37 

2-25 

2048 

7.90 

3-73 

9.40 

3-03 

10.  15 

2-37 

4096         9.19     3.82      10.93     3.07       12.48     2.54 

Ammonium  Chromium  Sulphate  (Green  Variety) 

The  mother  solution  was  prepared  by  heating  a  portion  of 
the  mother  solution  of  the  violet  variety  to  70°  for  about 
seven  hours  in  a  stoppered  bottle. 

Table  V. — Molecular  Conductivity 


V 

o9 

12°.  5 

25° 

35° 

8 

103.6 

133-2 

162.9 

185.3 

16 

119.7 

155-4 

190.6 

219.3 

32 

136.4 

178.2 

220.8 

255-1 

128 

172.3 

228.4 

288.1 

336.4 

512 

202.6 

274.4 

355-7 

423.2 

1024 

215.6 

294.2 

386.2 

471.2 

2048 

222.0 

3I3-5 

414.0 

518.4 

4096 

234-4 

328.4 

458.1 

593-8 

1 1 


Table  VI.  —  Temperature  Coefficients 

0°-12°.5 

12°.  5-25° 

25°-35a 

Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

units 

cent. 

units 

cent. 

units 

cent. 

2-37 

2.29 

2.38 

1.79 

2.24 

I.38 

2.70 

2  .26 

2.82 

1.82 

2.87 

I-5I 

3-34 

2-45 

3-41 

I.9I 

3-43 

i-55 

4-49 

2.6l 

4.78 

2.09 

4-83 

1.68 

5-74 

2.83 

6.  so 

2-37 

6-75 

i  .90 

6.  29 

2.92 

7.36 

2.50 

8.50 

2.20 

7-32 

3-37 

8.04 

2-57 

10.44 

2.52 

7-52 

3-21 

10.38 

3.16 

13-57 

2.96 

V 

8 

16 

32 

128 

512 

1024 

2048 

4096 


Ammonium  Copper  Sulphate,  (NH4)2Cu(SO4)2.6H2O 

The  mother  solution  was  standardized  by  determining  the 
sulphuric  acid  as  barium  sulphate,  and  the  copper  was  also 
determined  as  copper  oxide. 


Table  VII. — Molecular  Conductivity 


V 

0° 

12°.  5 

25' 

35- 

4 

106.3 

146.6 

190.4 

225.7 

8 

122.7 

169.9 

220.  7 

262.2 

32 

153-5 

213.8 

280.2 

334-3 

128 

187.8 

262.4 

346.7 

412  .6 

512 

221  .6 

312  .  I 

411.7 

495-7 

1024 

236.0 

333-5 

442.6 

532.5 

2048 

246.4 

347-9 

463.6 

560.0 

4096 

259  4 

367-3 

494.0 

597-3 

Table  VI II. —Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35* 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

4 

3-22 

3  03 

3  50 

2-39 

3-53 

1-85 

8 

3-78 

3.08 

4.06 

2-39 

4-15 

1.88 

32 

4.82 

3-H 

5-3i 

2.48 

5-41 

i  93 

128  5.97  3.18  6.74  2.57  6.59  1.90 

512  7.24  3.27  7.97  2.55  8.40  2.04 

1024  7.80  3.31  8.73  2.62  8.99  2.03 

2048  8.12  3.30  9.26  2.66  9.64  2.08 

4096  8.63  3.33  10.14  2.76  10.33  2.09 


12 

Sodium  Ferrocyanide,  Na4Fe(CN)6.  i2H2O 

The  mother  solution  was  made  up  by  direct  weighing  of  the 
anhydrous  salt. 

Table  IX. — Molecular  Conductivity 

V  0°  12°. 5  25°  35° 


8 

136.7 

194.9 

259.2 

3I3-4 

i6 

I5I-3 

215-5 

287.0 

347  •  7 

32 

167.  i 

238-5 

318.5 

386.2 

128 

203.5 

289.6 

385-9 

464.5 

512 

234.2 

334-1 

446.4 

543-2 

1024 

253-4 

361.7 

482.4 

581.2 

2048 

266.4 

380.3 

504.0 

612  .0 

4096 

275-7 

398.1 

527-1 

632.2 

Table  X. — Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35° 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

8 

4.66 

3-41 

5-14 

2  .64 

5-42 

2  .09 

16 

5-H 

3-40 

5-72 

2.65 

6.07 

2.  12 

32 

5-71 

3-42 

6.40 

2.68 

6.77 

2.13 

128 

6.89 

3-39 

7.70 

2.66 

7.86 

2.04 

512 

7-99 

3-4i 

8.98 

2.69 

9.68 

2.17 

1024 

8.66 

3-42 

9.66 

2.67 

9.88 

2-05 

2048 

9.11 

3-42 

9.90 

2.60 

10.80 

2.14 

4096 

9-79 

3-55 

10.32 

2-59 

10.51 

2.00 

Table  XL — Percentage  Disssociation 

0°  12°. 5  25°  35° 

8          49.58  48.96  49.18  49.57 


16 

54-88 

54-13 

54-45 

55-00 

32 

60.  61 

59-91 

60.43 

61  .09 

128 

73-8i 

72.74 

73-21 

73-47 

512 

84-95 

83.92 

84.69 

85-92 

1024 

91.91 

90.86 

9I-52 

91-93 

2048 

96.63 

95-53 

95.62 

96.81 

4096       100.00         loo.oo         loo.oo         100.00 

Potassium  Sodium  Sulphate,  KNaSO4 

The    mother    solution    was    standardized    by    determining 
sulphuric  acid  as  barium  sulphate. 


13 
Table  XII. — Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

4 

88.4 

122.5 

159-0 

189.6 

8 

96.  i 

146.6 

170.6 

2O9.  I 

32 

113.0 

I58.I 

2O7.2 

249.7 

128 

128.8 

179.0 

236.1 

284.5 

512 

135-6 

189.6 

250.8 

301.0 

1024 

140.8 

I97.I 

259-2 

3I3-2 

2048 

140.9 

198.2 

26l  .4 

316.2 

4096          144-3  202.6  267.6  322.1 

Table  XIII. — Temperature  Coefficients 

0°-12°.5  12°.  5-25°  25°-35° 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

4 

2-73 

3-09 

2  .92 

2.38 

3.06 

1.92 

8 

4.04 

4-30 

1.92 

1.30 

3-85 

I    79 

32 

3-68 

3-26 

3-93 

2-49 

4-25 

2.05 

128 

4.02 

3.12 

4-57 

2-55 

4.84 

2.05 

512 

4-32 

3-19 

4.90 

2.58 

5.02 

2  .OO 

1024 

4-50 

3-20 

4-97 

2.52 

5-4° 

2.08 

2048 

4-58 

3-25 

5.06 

2-55 

5-48 

2.  10 

4096        4.66      3.23        5.20      2.56        5.45      2.04 
Table  XIV. — Percentage  Dissociation 

V  0°  12°. 5  25°  35° 

4         61.26  60.46  59-42  58.88 

8         66.60  72.36  63.75  64.93 


32 

78.31 

78.03 

77-43 

77-54 

128 

89.26 

88.35 

88.23 

88-35 

512 

93-97 

93.58 

93-72 

93-47 

1024 

97-57 

97.28 

96.86 

97.26 

2048 

97.64 

97-83 

97-68 

98.19 

4096 

100.00 

IOO.OO 

100.00 

100.00 

Potassium  Aluminium  Sulphate,  KAl(SO4)2.i2H2O 
The    mother    solution    was    standardized    by    determining 
aluminium  as  aluminium  oxide. 

Table  XV. — Molecular  Conductivity 

V  0°  12°. 5  25°  35° 

78.9  108.9  I4°-3  l65-3 


32 

101  .2 

140.8 

182.2 

215-7 

128 

127.6 

177.7 

232.9 

283.7 

512 

158.8 

223.7 

294.9 

358.3 

1024 

177-8 

250.5 

332-7 

402.8 

2048 

197-5 

281.8 

378.4 

470.0 

4096 

218.8 

3I4-7 

425.5 

528.8 

14 
Table  XVI. — Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35° 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

8 

2.40 

3-04 

2-51 

2.30 

2.50 

1.78 

32 

3-17 

3-13 

3-31 

2-35 

3-35 

1.84 

128 

4.01 

3-14 

4.42 

2  49 

5.08 

2.18 

512 

5-19 

3-27 

5-69 

2-54 

6-34 

2.15 

1024 

5-81 

3-27 

6-57 

2.62 

7.01 

2  .  II 

2048 

6.74 

3-41 

7-73 

2.74 

9.  16 

2.42 

4096 

7.67 

3-51 

8.86 

2.82 

10-33 

2-43 

Potassium  Nickel  Sulphate,  K2Ni(SO4)2.6H2O 
The    mother    solution    was    standardized    by    determining 
sulphuric  acid  as  barium  sulphate  and  also  by    determining 
nickel  as  oxide. 

Table  XVII. — Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

8 

122  .6 

170.7 

221  .9 

265.3 

32 

155-4 

217.0 

283-8 

339-7 

128 

187-5 

263.0 

344-8 

414.1 

512 

219.6 

309  3 

407.7 

490.7 

1024 

235-5 

331-2 

437-1 

527-1 

2048 

249  5 

349-9 

463.0 

560.1 

4096 

26o.8 

367-9 

487.4 

588.1 

Table  XVIII. — Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35< 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

8 

3-85 

3-14 

4.  10 

2.40 

4-34 

1.96 

32 

4  93 

3.17 

5-32 

2-45 

5-59 

i-97 

128 

6.04 

3.22 

6-54 

2.48 

6-93 

2.01 

512 

7-18 

3-27 

7-87 

2-54 

8.30 

2.O4 

1024 

7.66 

3-25 

8.47 

2.56 

9.00 

2.06 

2048 

8.03 

3.22 

9  05 

2-59 

9.71 

2.09 

4096         8.57      3.29        9.56       2.60       10.07       2.07 
Table  XIX. — Percentage  Dissociation 

V  0°  12°. 5  25°  35° 

47.01        46.40        45.53        45.11 


32 

59-59 

58.98 

58.23 

57-76 

128 

71.89 

71.49 

70.74 

70.41 

512 

84.20 

84-07 

83.65 

83.44 

1024 

90.30 

90.02 

89.68 

89.63 

2048 

95  67 

95  ii 

94-99 

95-24 

4096 

IOO.OO 

IOO.OO 

IOO.OO 

100.00 

15 

Potassium  Chromium  Sulphate  ( Violet  Variety) , 
KCr(SO4)a.i2HaO 

The  mother  solution  was  standardized  by  determining 
chromium  as  chromic  oxide  and  also  by  determining  sulphuric 
acid  as  barium  sulphate. 


Table  XX. 

—  Molecular  Conductivity 

V 

0° 

12°.  5 

25° 

35° 

8 

75-8 

105.0 

135-3 

159    4 

16 

87-3 

121  .2 

157-3 

185.3 

32 

99.0 

I38.I 

179.6 

2II.3 

128 

127.0 

179-5 

236.7 

279.9 

512 

161  .  i 

232.0 

3II-5 

374-5 

1024 

186.6 

271  .6 

369.6 

443-8 

2048 

213-3 

3I4-2 

428.8 

520.6 

4096 

245.8 

364.8 

500.1 

613.9 

Table  XXI. — Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35' 


Cond.  Per  Cond.  Per  Cond.  Per 


V 

units 

cent. 

units 

cent. 

units 

cent. 

8 

2-34 

3.09 

2.42 

2.31 

2.4I 

1.78 

16 

2.71 

3.10 

2.89 

2.38 

2.80 

1.78 

32 

3-13 

3.I6 

3-32 

2.40 

3-17 

1.77 

128 

4.20 

3.31 

4-58 

2-55 

4-32 

1.82 

512 

5.67 

3-52 

6.36 

2.74 

6.30 

2  .02 

1024 

6.80 

3-64 

7-84 

2.89 

7-42 

2.01 

2048 

8.07 

3-78 

9.17 

2  .92 

9.18 

2.14 

4096 

9  52 

3-87 

10.82 

2.97 

11.38 

2.28 

Potassium  Chromium  Sulphate  (Green  Variety) 
The  mother  solution  was  prepared  by  heating  a  portion  of 
the  mother  solution  of  the  violet  variety  to  70°  for  about  seven 
hours  in  a  stoppered  bottle. 

Table  XXII. — Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

8 

101  .0 

I30.I 

158.4 

179.6 

16 

H9  3 

154.0 

I88.I 

213.2 

32 

137  8 

179  3 

219-5 

249-3 

128 

177.7 

234  4 

290.6 

333-5 

512 

210.9 

283-5 

359-i 

426.6 

1024 

229.7 

310.9 

399  -6 

479-0 

2048 

247.0 

339-5 

441-3 

539-1 

4096 

273.1 

379-4 

500.3 

616.2 

i6 


Table  XXIII.— 

Temperature  Coefficients 

0°-12 

.  5 

12°.  5-25° 

25°-35° 

Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

8 

2-33 

2.31 

2.26 

1.74 

2  .  12 

i-34 

16 

2.78 

2-33 

2-73 

1.77 

2.51 

i-33 

32 

3-32 

2.4I 

3-22 

I.  80 

2.98 

1.36 

128 

4-54 

2-55 

4-50 

1.92 

4.29 

1.48 

512 

5-8i 

2.76 

6.05 

2.13 

6-75 

1.88 

1024 

6.50 

2.83 

7.10 

2.28 

7-94 

1.99 

2048 

7.40 

3.00 

8.14 

2.40 

9-78 

2.22 

4096 

8.50 

3  -ii 

9.67 

2-55 

11  -59 

2.32 

Calcium  Formate,  Ca(OOCH)2 

The    mother    solution    was    standardized    by    determining 
calcium  as  the  sulphate. 

Table  XXIV. — Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

4 

58.4 

81.7 

IO7  .  I 

128.6  ' 

8 

67.2 

94  4 

124.5 

149-7 

32 

81  .4 

II5-3 

I53-I 

184.7 

128 

92.2 

131.2 

174-3 

211  .6 

512 

95-7 

135-5 

l8l.9 

223-5 

2048 

101  .4 

144.6 

190.4 

230.6 

4096 

101.3 

145-4 

190.6 

229.2 

Table  XXV . — Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35< 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

4 

I 

.86 

3 

19 

2.03 

2-49 

2 

15 

2 

.01 

8 

2 

.18 

O 

24 

2.41 

2-55 

2 

•52 

2 

.02 

32 

2 

.70 

o 

•32 

3.02 

2.62 

3 

.16 

2 

.06 

128 

3 

.  12 

^ 

.38 

3-45 

2.63 

3 

•73 

2 

•H 

512 

3 

.18 

o 

32 

3-7i 

2-74 

4 

.16 

2 

.29 

2048 

3 

.46 

3 

.41 

3-66 

2-53 

4 

.02 

2 

.  II 

4096 

3 

•53 

«3 

48 

3-62 

2-49 

3 

.86 

2 

•03 

Table  XXVL 

—  Percentage  Dissociation 

V 

0 

o 

12°.  5 

25° 

35° 

4 

57- 

65 

56-19 

56.19 

56 

.  II 

8 

66. 

34 

64.92 

65-32 

65 

31 

32 

80. 

36 

79-30 

80-33 

80.58 

128 

9i- 

02 

90.23 

91-45 

92 

•32 

512 

94- 

47 

93-19 

95-44 

97 

51 

2048   loo.oo     99-45     99-89    100.00 
4096    ....     100.00    loo.oo 


17 

Calcium  Chromate,  CaCrO4 

The  mother  solution  was  standardized  by  titrating  with 
ferrous  ammonium  alum. 

Table  XXV 1 1. —Molecular  Conductivity 

V                    0°                      12°. 5                     25°  35° 

8            57.7             80.9           105.8  125.4 

1 6           64.6             90.4           118.5  I4°-9 

32            72.2           101.4           I33-1  158.2 

128           91.2           126.9           *67-5  200.8 

512    106.7     150-0     198-7  239.5 

1024    i i i. 6     157-3     208.8  253.3 

2048    114 .4     160.8     214.0  264.0 

4096    116.1     162.5     216. i  261.6 


v 
8 

16 

32 

128 

512 

1024 

2048 

4096 

Table  XXIX — Percentage  Dissociation 

V  0°  12°. 5  25°  35° 

8  49.70  49.78  48.96  47.94 

16  55-64  55-63  54-85  53-86 

32  62.19  62.40  61.59  60.47 

128  78.55  78.09  77.51  76.76 

512  91.90  92.31  91.95  91.55 

1024      96 . I 2       96 . 80       96 . 62       96 . 83 

2048    98.54     98.95     99 -°3    100.00 
4096   100.00    100.00    100.00     .... 

Zinc  Nitrate,  Zn(NO3)2.6H2O 

The  mother  solution  was  standardized  by  determining  zinc 
as  zinc  oxide. 


Table  XXVIII.  —  Temperature  Coefficients 

0°-12°.5 

12°.  5-25° 

25°-35° 

Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

units 

cent. 

units 

cent. 

units 

cent. 

1-85 

3-21 

1.99 

2.46 

I  .96 

1.85 

2  .06 

3-19 

2.25 

2-49 

2.24 

1.89 

2-33 

3-23 

2-54 

2-51 

2.51 

1.89 

2.86 

3-14 

3-25 

2.56 

3-33 

i  99 

3-46 

3-24 

3-90 

2.60 

4.08 

2.05 

3-66 

3.28 

4.12 

2.62 

4-45 

2.13 

3-71 

3-24 

4.26 

2.65 

5-oo 

2-34 

3-7i 

3-20 

4.29 

2.64 

4-55 

2.  II 

i8 
Table  XXX. — Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

4 

80.6 

1  10  .  8 

146.6 

I7I.2 

i 

87.6 

121  .2 

157  2 

188.5 

32 

IOO.O 

139.2 

I82.I 

2I9.O 

128 

110.4 

I54-I 

202  .6 

243-5 

512 

114.  1 

164.9 

210.  I 

254-3 

1024 

117.1 

165.0 

216.6 

261.3 

2048 

120.4 

169.2 

222  .4 

270.2 

4096 

124.4 

175  -0 

229.  I 

279.4 

Table  XX XL — Temperature  Coefficients  * 

0°-12°.5  12°. 5-25°  25°-35' 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

4 

2.42 

.3-00 

2.86 

2.58 

2  .46 

1.68 

8 

2.69 

•3-07 

2.88 

2.38 

3-13 

i  99 

32 

3-34 

3-34 

3-43 

2  .46 

3-69 

2.03 

128 

3-50 

3-17 

3.88 

2.52 

4.09 

2  .02 

512 

4.06 

3-56 

3.62 

2  .20 

4.42 

2.  10 

1024 

3-83 

3-27 

4-13 

2.50 

4-47 

2.06 

2048 

3-90 

3-24 

4.26 

2.52 

4.78 

2.15 

4096 

4-05 

3-26 

4-33 

2-47 

5-03 

2.  2O 

Table  XXXIL — Percentage  Dissociation 


V 

0° 

12°.  5 

25° 

35° 

4 

64.79 

63-3I 

63-99 

61  .27 

8 

70.42 

69.26 

68.62 

67.47 

32 

80.39 

79-54 

79.48 

78.38 

128 

88.75 

88.06 

88.43 

87.15 

512 

91.92 

94-23 

91.71 

91  .02 

1024 

94  13 

94.29 

94-54 

93-52 

2048 

96.78 

96.68 

97.07 

96.71 

4096    IOO.OO     IOO.OO     IOO.OO     IOO.OO 

Zinc  Acetate,  Zn(C2H3O2)2 

The  mother  solution  was  standardized  by  determining  zinc 
as  zinc  oxide. 

Table  XXXI 1 1. —Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

4 

27.8 

38.0 

48.0 

55-0 

8 

37-7 

52.2 

66.6 

77-2 

32 

55-5 

78.6 

103.0 

122.4 

128 

70.0 

IOO-7 

134-2 

162.1 

512 

78.6 

II3-7 

153-2 

185-5 

1024 

79  9 

116.  i 

156-7 

191  .6 

2048 

83-2 

120.8 

163.2 

200.  i 

4096 

83.8 

121.3 

163.4 

2OI  .  I 

19 


Table  XXXIV. 

0°-12°.5 

,  —  Temperature  Coefficients 

12°.  5-25°                             25 

°-35° 

Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

4 

0 

.81 

2 

•91 

0.80 

2.  II 

o 

.70 

I 

-46 

8 

I 

.16 

3 

.08 

1.  15 

2.20 

I 

.06 

I 

-59 

32 

I 

-85 

3 

•33 

i  95 

2.48 

I 

94 

I 

.88 

128 

2 

•45 

3 

•50 

2.68 

2.66 

2 

79 

2 

.08 

512 

2 

.81 

3 

•58 

3.16 

2.78 

3 

•23 

2 

.  ii 

1024 

2 

90 

3 

•63 

3-25 

2.79 

3 

49 

2 

•23 

2048 

o 

OI 

3 

.61 

3-39 

2.81 

3 

.69 

2 

.26 

4096 

3 

00 

3 

•58 

3-37 

2.78 

3 

-77 

2 

•3i 

Table  XXXV. 

—  Percentage  Dissociation 

V 

0 

0 

12°.  5 

25° 

35° 

4 

33- 

17 

3i 

•33 

29.38 

27 

•35 

8 

44- 

99 

43 

•03 

40.76 

38 

•39 

32 

66. 

23 

64 

.80 

63-03 

60 

-87 

128 

83- 

53 

83 

.02 

82.13 

80 

.61 

512 

93- 

79 

93 

•73 

93-76 

92 

.24 

1024 

95- 

34 

95 

•7i 

95-9P 

95 

.28 

2048 

99- 

28 

99 

•59 

99.86 

99 

•50 

4096 

100. 

00 

100 

.00 

100.00 

IOO 

.00 

Lead  Acetate, 

The    mother    solution    was    standardized    by    determining 
lead  as  lead  sulphate. 


Table  XXXVI. — -Molecular  Conductivity 


V 

0° 

12°.  5 

25° 

35° 

4 

II  .2 

16.4 

22  .  I 

27.0 

8 

16.0 

23-3 

31.2 

37-8 

32 

28.8 

41.4 

54-9 

66.2 

128 

46.4 

66.3 

87.1 

104.2 

512 

65.3 

92.7 

I23.I 

146.2 

1024 

74-5 

108.2 

I39-I 

167.2 

2048 

84-3 

II9.4 

156.8 

189.1 

4096 

87.8 

124.6 

165.5 

198.7 

20 


Table  XX XV II. —Temperature  Coefficients 

0°-12°.5  12°. 5-25°  25°-35° 


Cond. 

Per 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

units 

cent. 

4 

0 

.41 

3 

.66 

0.46 

2.8l 

0. 

49 

2 

.22 

8 

0 

•58 

3 

-63 

0.63 

2.70 

o. 

66 

2 

.  12 

32 

I 

.01 

3 

•50 

I.  08 

2.61 

I  , 

13 

2 

.06 

128 

I 

•59 

3 

•42 

1.66 

2.50 

I  , 

71 

T 

.96 

512 

2 

•19 

3 

•35 

2-43 

2.62 

2  , 

31 

i 

.88 

1024 

2 

.70 

3 

.62 

2.47 

2.28 

2, 

81 

2 

.02 

2048 

2 

.81 

3 

•34 

2.99 

2.50 

o 

23 

2 

.06 

4096 

2 

•94 

3 

•35 

3-27 

2.62 

3 

32 

2 

•15 

Table  XXXVIII. 

—  Percentage  Dissociation 

V 

0 

0 

12°.  5 

25° 

35° 

4 

12 

.76 

13.16 

13- 

35 

13- 

59 

8 

18 

.22 

18.70 

18. 

85 

19- 

02 

32 

32 

.80 

33-23 

33- 

17 

33- 

32 

128 

52 

-85 

53-21 

52. 

63 

52. 

44 

512 

74 

-38 

74.40 

74- 

38 

73- 

58 

1024 

84 

.86 

86.84 

84- 

05 

84. 

15 

2048 

96 

.02 

95-83 

94- 

74 

95- 

*7 

4096 

100 

.00 

100.00 

100. 

oo 

100. 

00 

Ammonium  Aluminium  Sulphate,  NH4Al(SO4)2.i2H2O 
The  mother  solution  was  standardized  by  determining  sul- 
phuric acid  as  barium  sulphate. 


v 

8 

16 

64 

128 

512 

2048 


Table  XXXIX. 

35° 

168.8 
202.3 
261.5 
284.8 


485-8 


-Molecular  Conductivity 

50°  65° 

203 .5  236 . 5 

247.5  288.0 

325-8  384-8 

347-5  426.3 

477-5  573-5 

643-1  831.5 


Table  XL. — Temperature  Coefficients 

35°-50°  50°-65° 


Cond 

Per 

Cond. 

Per 

V 

units. 

cent. 

units 

cent. 

8 

2.31 

1-37 

2  .20 

.08 

16 

3.01 

1.48 

2  .  70 

.09 

64 

4  29 

I  .64 

3-93             'i 

.21 

128 

4.18 

i-47 

5  •  25 

•51 

512 

7-44 

2.03 

6.40 

•34 

2048 

10.49 

2.16 

12.56 

•95 

21 

Disodium  Phosphate,  HNa2PO4.i2H2O 

The  mother  solution  was  standardized  by  determining  the 
phosphoric  acid  as  magnesium  pyrophosphate. 

Table  XLI. — Molecular  Conductivity  and  Dissociation 

35°  50°  65° 


V 

8 
32 

128 
512 

2048 

V 

8 
32 

128 

512 

2048 

Hv 

141.8 
176.8 
206.5 
224.3 
229.5 

Table 

a                   flv                      a                     Pv 
6l.8           184.1           6l-5           228.0 
77.0          228.2           76.3           287.9 

90.9       269.0       89.8       334-4 
97.8       292.7       97.8       376.1 
loo.o       299.3     loo.o     (355.4) 

XLII.  —  Temperature  Coefficients 

35°-50°                                            50°-65° 

;  i 
60 
76 
88 

IOO 

i 

.6 
.6 
•9 

.0 

Cond. 
units 

2.82 

3-43 
4.17 

4-56 
4-65 

Per 
cent. 

1.99 

i  94 

2  .02 
2.03 
2.03 

Cond. 
units 

2-93 
3-98 
4-36 
5-56 
4-65 

Per 

cent. 

i-59 
1.74 
1.62 
i  .90 

Sodium  Tetraborate, 
The  mother  solution  was  standardized  as  the  anhydrous 
salt. 

Table  XL/77. — Molecular  Conductivity  and  Dissociation 

35°  50°  65° 


V 

16 

141  3 

a 
70.9 

P-v                        a 
182.8           67.6 

231-3 

a 
64 

4 

32 

I57-I 

78.8 

204.0       75 

•5 

256.2 

71 

3 

128 

172.4 

86.5 

224.1       82 

9 

281.6 

78 

4 

512 

186.7 

93-6 

247.8       91 

-7 

316.7 

88 

,1 

2048 

199.4 

IOO.O 

270.3     loo 

.0 

359-3 

IOO 

.0 

Table  XLIV  .—Temperature 

Coefficients 

35°-50° 

50°-65° 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

16 

2 

77 

I.96 

3-23 

I 

.76 

32 

3 

13 

1.99 

3-48 

I 

-7i 

128 

*J 

45 

2.OO 

3-83 

I 

7i 

512 

4 

01 

2-15 

4-59 

I 

-85 

2048 

4 

•73 

2-37 

5-93 

2 

19 

22 


Potassium  Aluminium  Sulphate,  KAl(SO4)2.i2H2O 
The  mother  solution  was  standardized  by  determining  sul- 
phuric acid  as  barium  sulphate. 


v 

4 

8 

32 

128 

512 

2048 


Table  XLV. — Molecular  Conductivity 

35°  50°  65° 

142.3  172.5  196.1 

165.3  207.5  240.6 

215  7       255.1       317.4 


283.7 
358.3 

470.0 


356.9 
446.9 
626.4 


426.2 

557-1 
796.4 


Table  XLV  I. — Temperature  Coefficients 


3S°-50° 


50°-65° 


Cond.                     Per 

Cond.                    Per 

V 

units                    cent. 

units                   cent. 

4 

2.01                      .41 

i-57             0.87 

8 

2  .  8  i                 .70 

2.21                      .06 

32 

2.63                      .22 

4-15                      -63 

128 

4.88                      .72 

4.62                      .29 

512 

5  9i                 65 

7-35                -64 

2048 

10.42                   2.22 

11.33                -81 

Potassium  Sulphocyanate,  KCNS 

The  mother  solution  was  prepared  by  direct  weighing. 
Table  XLV II. — Molecular  Conductivity  and  Dissociation 


35 ( 


50C 


65' 


V 

nv 

a 

Pv 

a 

V-V 

a 

4 

127.6 

79  2 

160.2 

77-6 

191  .  1 

76.2 

8 

132.9 

82.4 

166.7 

80.8 

201  .8 

80.4 

32 

142-3 

88.3 

179.6 

87.0 

219.6 

87-5 

128 

H9-3 

92.6 

190.0 

92.1 

232.4 

92  .6 

512 

153-7 

95-4 

192.6 

93  3 

239-3 

95-4 

2048 

161  .2 

100.  0 

206.4 

100.  0 

250.9 

IOO.O 

Table  XLV  III. —Temperature  Coefficients 


35°-50° 


50°-65° 


Cond. 

Per 

V 

units 

cent. 

4 

2.17 

.70 

8 

2.25 

.69 

32 

2-49 

•75 

128 

2.74 

.84 

512 

2.60 

.69 

2048 

3.01 

.86 

Cond. 

Per 

units 

cent. 

2.06 

I  .29 

2-34 

I  .40 

2.67 

1-49 

2.83 

i  49 

3   ii 

1.62 

2.97 

1.44 

23 

Monopotassium  Phosphate,  H2KPO4 

The  mother  solution  was  standardized  by  determining  phos- 
phoric acid  as  magnesium  pyrophosphate. 

Table   XLIX. — Molecular   Conductivity  and   Dissociation 

35°  50°  65° 


V 

V-v 

a 

fiv 

a 

P-v 

a. 

8 

310.4 

63-8 

391.6 

64-5 

477-2 

61.2 

32 

380.0 

78.1 

481.2 

79-2 

588.4 

75-5 

128 

424-3 

87.2 

537-6 

88.5 

661.2 

84.8 

512 

452.3 

93  -o 

573-1 

94-4 

708.2 

90.9 

2048 

471-5 

96.9 

599-9 

98.8 

740.9 

95-1 

8192 

486.4 

100.  0 

621  .4 

IOO.O 

779-4 

IOO.O 

Table  L. — Temperature  Coefficients 

35°-50°  50°-65° 


Cond.  Per  Cond.  Per 

units  cent.  units  cent. 


8 

5-41 

i  74 

5-7i 

i  .46 

32 

6-75 

1.78 

7-15 

i  49 

128 

7-55 

1.78 

8.24 

i-53 

512 

8.05 

1.78 

9.01 

i-57 

2048 

8.56 

1.81 

9.40 

1-58 

8192 

9.00 

1.82 

io-53 

i  .69 

Potassium  Acetate,  KC2H3O2 

The    mother    solution    was    standardized    by    determining 
potassium  as  the  sulphate. 

Table  LL — Molecular  Conductivity  and  Dissociation 

35°  50°  65° 


V 

Hv 

a 

lh) 

a 

V-v 

a. 

4 

94- 

4 

75- 

40 

125.6 

78. 

84 

142 

.  I 

72. 

13 

8 

102  . 

7 

82. 

03 

131.6 

82. 

61 

1  60 

•4  . 

81. 

42 

32 

112  . 

o 

89. 

46 

147.0 

92 

28 

1  80 

.8 

91. 

78 

128 

118. 

7 

94- 

81 

154.6 

97 

05 

184 

•5 

93 

66 

512 

125. 

2 

100. 

00 

159  3 

IOO. 

00 

194 

•9 

98. 

94 

2048 

.123. 

3 

«  •  •  • 

157-7 

197 

.0 

IOO. 

00 

Table  LI  I. — Temperature  Coefficients 


35°-50° 


50°-65° 


Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

4 

2.08 

2.20 

I  .  10                 ( 

).88 

8 

i-93 

1.88 

I  .92 

.46 

32 

2-33 

2.08 

2.25 

•53 

128 

2.40 

2.02 

2.00 

.29 

512 

2.27 

1.81 

2-37 

•49 

2048 

2.29 

1.86 

2.62 

.66 

Calcium  Chloride, 

The  mother  solution  was  standardized  by  determining  cal- 
cium as  carbonate  and  chlorine  by  Mohr's  method. 

Table  LIII. — Molecular  Conductivity  and  Dissociation 

35°  50°  65° 


V 

Vv 

a 

ftv 

a 

Hv 

a 

4 

189 

.  I 

63 

41 

237 

-7 

62  .  22 

29O. 

4 

61 

16 

8 

208 

.  I 

69, 

78 

258 

•5 

67-67 

3l8. 

7 

67 

12 

32 

242 

.0 

81 

15 

306 

•5 

80.24 

378- 

5 

79 

.72 

128 

267 

.  I 

89 

57 

34° 

.8 

89.21 

418. 

9 

88 

.22 

512 

283 

•5 

95 

.07 

362 

4 

94.87 

452. 

5 

95 

30 

2048       298.2     100.0      382.0     100.00    474.8  100.00 
Table  LIV. — Temperature  Coefficients 

35°-50°  50°-65° 


Cond. 

Per 

Cond. 

Per 

V 

units                  c 

ent. 

units 

cent. 

4 

3-24        '•;) 

[-71 

3-51 

1.48 

8 

3-36 

.62 

4-OI 

i-55 

32 

4-3°               :1 

.78 

4.80 

i-57 

128 

4.91 

.84 

5-21 

i-53 

512 

5-26 

.86 

6.01 

1.66 

2048 

5-59          :i'i 

.88 

6.  19 

1.62 

Magnesium  Chloride,  MgCl2.6H2O 

The  mother  solution  was  standardized  by  determining 
magnesium  as  magnesium  pyrophosphate  and  chlorine  by 
Mohr's  method. 


Table  LV. — Molecular  Conductivity  and  Dissociation 


35' 


50 c 


65' 


4 

179-8 

62  .  17 

228.0 

61  .09 

280.6 

60.27 

8 

196-5 

67-95 

249.7 

66.91 

303.8 

65-25 

32 

231.6 

8o.o8 

294.7 

78.97 

364.8 

78.35 

128 

249-8 

86.37 

3II.8 

83-55 

401  .6 

86.25 

512 

269-9 

91  .20 

348.3 

93-33 

433-1 

93.02 

2048 

289.2 

IOO.OO 

373-2 

100.00 

465-6 

100.00 

Table  LVL — Temperature  Coefficients 

35°-50°  50°-65° 


Cond. 

Per 

units 

cent. 

3-21 

•79 

3-55 

.81 

4.21              l 

.82 

4-13 

•65 

5-23 

•94 

5.60 

•94 

Cond. 

Per 

units 

cent. 

3-51 

•54 

3.6l 

•45 

4.67 

•58 

5-93 

.90 

5-65 

.62 

6.16 

65 

V 

4 

8 

32 
128 
512 

2048 


Manganese  Sulphate,  MnSO4.4H2O 

The  mother  solution  was  standardized  by  determining 
manganese  as  manganous  pyrophosphate  and  sulphuric  acid 
as  barium  sulphate. 

Table  LVIL — Molecular  Conductivity 


V 

35° 

50° 

65 

0 

4 

78. 

0 

88. 

0 

108 

•3 

8 

92 

6 

112. 

8 

130 

.0 

32 

128. 

5 

156. 

4 

181 

.8 

128 

166 

7 

204. 

I 

241 

9 

512 

219. 

4 

277. 

5 

338 

•  7 

2048 

246. 

0 

326. 

7 

404 

.6 

Table  LVIII 

.  —  Temperature 

Coefficients 

35°-50° 

50°-65 

* 

Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units 

cent. 

4 

0 

67 

O 

.86 

I 

35 

53 

8 

I 

35 

I 

46 

I 

15 

04 

32 

I 

86 

I 

•45 

I 

69 

08 

128 

2 

49 

I 

•49 

2 

52 

24 

512 

o 

87 

I 

•76 

4 

08 

47 

2048 

c 

38 

2 

19 

5 

19 

• 

59 

26 


Ferric  Chloride,  FeCl3.6H2O 

The  mother  solution  was  standardized  by  determining  iron 
as  ferric  oxide. 

Table  LIX. — Molecular  Conductivity  and  Dissociation 

35°  50°  65° 


V 

I'v 

a 

4 

214 

-J 

16 

92 

8 

276 

5 

21 

•83 

32 

424 

•1 

33 

•52 

128 

827 

i 

65 

.29 

512 

1050 

7 

82 

•94 

2048 

1266 

8 

100 

.00 

269.5 

346-9 
515.8 

1037.6 
1405.4 


17.71 

23-32 
34.68 

69.75 

94.48 


1487.5   100.00 


327.0          19.39 


I5I2.5          89.71 

1685.9     ioo. oo 

1673.6 


Table  LX. — Temperature  Coefficients 

35°-50°  50°-65° 


Cond. 

Per 

V 

units 

cent. 

4 

3-68 

1.72 

8 

4.69 

1.70 

32 

6.07 

i-43 

128 

14.00 

i  .69 

512 

23-6 

2.25 

2048 

14.7 

i  .60 

Cond. 

units 

3.83 


31-7 
I8.7 
I2.4 


Per 
cent. 

1.42 


3-85 

i-33 
0.83 


Chromium  Sulphate  (Green  Variety) 

The    mother    solution    was    standardized    by    determining 
chromium  as  chromic  oxide. 

Table  LXL — Molecular  Conductivity 


V 

35° 

50° 

65° 

4 

128.2 

160.0 

189.6 

8 

183.5 

227.8 

262  .9 

32 

302.0 

354-4 

417.4 

128 

433-9 

522.7 

606.0 

512 

673-3 

811.1 

977-3 

2048 

961  .  i 

1207.8 

1534-7 

Table  LXII.  —  Temperature  Coefficients 

35°-50° 

50°-65° 

Cond. 

Per                     Cond. 

Per 

V 

units                    cent.                    units  - 

cent. 

4 

2.  12 

•65             i  97 

•23 

8 

2-95 

-61             2.34 

•03 

32 

3-49 

.16             4.20 

•19 

128 

5  •  92 

-34             5-55 

.06 

512 

9.19 

-37           ii.  oS 

•37 

2048 

16.45 

.71           21.79 

.80 

Nickel  Nitrate,  Ni(NO3)2.6H2O 
The*  mother    solution    was    standardized    by    determining 

AM 

nickel  as  nickel  oxide. 

Table  LXIII. — Molecular  Conductivity  and  Dissociation 


35 c 


50C 


65' 


V 

Ai 

a 

V-v 

a 

V-v 

a 

4 

200.8 

61  .0 

252.4 

60.  I 

306.6 

59  4 

8 

216.8 

65-8 

276.3 

65-6 

343-5 

66.6 

32 

260.  1 

79-0 

330.3 

78.6 

402.4 

78.0 

128 

289.7 

89.8 

369.2 

87.9 

453-2 

87.8 

512 

314-2 

95-4 

399-7 

95-2 

494.8 

95-9 

2048       329.3     ioo. o      420.0       ioo. o       516.0       loo. o 
Table  LXIV .—Temperature  Coefficients 


35°-50° 


50°-65< 


Cond. 

Per 

Cond. 

Per 

V 

units 

cent. 

units                      c 

ent. 

4 

3-44             i 

[-71 

3-6i 

•43 

8 

3-97 

-83 

4.48 

.62 

32 

4.68 

.80 

4.81 

.46 

128 

5-30           | 

-83 

5.60 

•  52 

512 

5-70 

.81 

6-34 

59 

2048 

6.05 

.84 

6.40 

•52 

Nickel  Sulphate,  NiSO4.6H2O 

The    mother    solution    was    standardized    by    determining 
sulphuric  acid  as  barium  sulphate. 

Table  LXV.  —  Molecular  Conductivity 

V  35°  50° 

4  78.6  95.5 

8  93-i  ii5-5 

32  127.0  158.2 

128  171.8  215.6 

512  219.4  278.9 

2048  264.0  34T-3 


65° 

in. 8 

135-7 
187.8 
259.8 
339-7 
425-7 


*  Table  LXV  I.  —  Temperature  Coefficients 


35°-50° 


50°-65< 


Cond. 

Per 

Cond. 

Per 

V 

units                   < 

:ent. 

units                   < 

:ent. 

4 

I    13 

•44 

1.09 

.14 

8 

i  49 

.60 

i-35 

-17 

32 

2.08 

.64 

i  97 

•25 

128 

2  .92 

.70 

2-95 

•37 

512 

3-97 

.81 

4-05 

•45 

2048 

5   15 

•95 

5-63 

•65 

28 


Cobalt  Sulphate,  CoSO4.7H2O 

The  mother  solution  was  standardized  by  determining  sul- 
phuric acid  as  barium  sulphate. 

Table  LXVII. — Molecular  Conductivity 


v 

4 

8 

32 

128 

512 

2048 


35° 
80.0 

94-9 
129.  i 

172.5 
229.8 
264.8 


50° 

95-6 

117.2 
160.0 
203.4 
2.90.7 
340-3 


65° 
II2.7 

137-5 
189.6 
256.6 
346.0 

421 .6 


Table  LXVIIL — Temperature  Coefficients 

35°-50  50°-65° 


Cond. 

Per 

V 

units 

cent. 

4 

I  .04 

1.30 

8 

I    49 

i-57 

32 

2.06 

i-59 

128 

2.06 

i.,  1.9 

512 

4.06 

1.76 

2048 

5-03 

i  .90 

Cond. 
units 

Per 
cent. 

I  .  14 

•19 

1-35 

•15 

i   97 

•23 

3-55 

•74 

3-49 

.20 

5-42             i 

t-59 

Copper  Sulphate,  CuSO4-5H2O 

The  mother  solution  was  standardized  by  determining  copper 
as  copper  oxide  and  sulphuric  acid  as  barium  sulphate. 

Table  LXIX. — Molecular  Conductivity 

V  35°  50°  65° 

4                   75-6  93-8  107.4 

8                   90.5  109.1  124.5 

126.1  152.7  173.8 

170.7  210.3  247.3 

222.7  279.1  337-7 

266.3  343-3  422.7 

Table  LXX.— Temperature  Coefficients 


32 

128 

512 

2048 


35°-50° 


50°-65° 


Cond. 

Per 

Cond. 

Per 

V 

units                    c 

ent. 

units 

cent. 

4 

I  .21                  3 

.60 

0.91 

0.97 

8 

1.24                 3 

•37 

I  .02 

o-93 

32 

i-77           'J 

.40 

I.4I 

0.92 

128 

2.64 

•55 

2-45 

1.16 

512 

3-76 

.69 

3  9i 

i  .40 

2048 

5-13 

i-93 

5-29 

i-54 

DISCUSSION  OF 

Salts  Studied  from  o°  to  35° 

The  conductivity  data  (Tables  XXIV  to  XXXVIII)  for 
the  salts  derived  from  diacid  bases  are  of  the  same  general 
character.  This  is  best  seen  by  drawing  curves.  Fig.  I  shows 


32   128          512  1024 

Concentration 
Fig.  I. — Zinc  acetate 


2048 


conductivity-concentration  curves  for  zinc  acetate,  which 
may  be  taken  as  an  example  of  these  salts.  The  diagrams  for 
the  other  members  of  the  group  are  similar,  except  that  the 
curve  is  much  flattened  in  the  cases  of  lead  acetate  and  calcium 
chromate.  This  is  apparent  in  Fig.  II,  which  gives  the 
conductivity-concentration  curves  for  lead  acetate. 

Lead  acetate  presents  a  number  of  exceptions.  In  concen- 
trated solutions  it  has  the  smallest  molecular  conductivity 
and  dissociation  of  any  of  the  salts  studied.  At  infinite 
dilution,  however,  the  conductivity  is  nearly  the  same  at  all 
temperatures  as  for  zinc  acetate.  Again,  lead  acetate  shows 
the  smallest  temperature  coefficients  of  conductivity  at  high 
temperatures,  and  the  most  rapid  increase  with  dilution  of 
any  of  the  salts  brought  within  the  scope  of  this  investigation. 

It  has  been  known  that  dissociation  seems  to  be  nearly 
independent  of  temperature  over  the  range  of  temperature  at 


30 

which  my  work  was  done,  but  in  general  decreases  as  the  tem- 
perature rises.  This  is  true  of  all  but  four  of  the  salts  included 
in  this  investigation. 

The  four  apparent  exceptions  are  potassium  acetate,  cal- 
cium formate,  lead  acetate  and  sodium  ferrocyanide.  Potas- 
sium acetate  shows  no  well-marked  change  in  the  dissocia- 
tion with  temperature.  Dissociation  apparently  increases  as 
the  temperature  rises  in  the  cases  of  calcium  formate  and 
sodium  ferrocyanide.  The  same  is  true  of  lead  acetate  in 
concentrated  solutions.  It  is  intended  to  study  farther  the 
dissociation  of  these  apparently  exceptional  salts. 


J2    128  5/2  T024  2O48 

Concentration 
Fig.  II.— I<ead  acetate 

The  complex  salt  sodium  ferrocyanide  has  high  conduc- 
tivity and  large  temperature  coefficients  of  conductivity.  The 
percentage  coefficients  are  remarkably  constant  at  the  various 
dilutions.  The  value  for  //^  was  hardly  reached  at  the  high- 
est dilution  used,  which  is  probably  due,  in  part  at  least,  to 
the  breaking  down  into  simpler  ions  in  the  more  dilute  solutions. 
Hydrolysis  also  probably  takes  place. 

The  remaining  salts  studied  over  the  lower  range  in  tem- 
perature are  double  salts  and  all  are  sulphates.  Ammonium 
copper  sulphate  and  potassium  nickel  sulphate  yield  very 
similar  conductivity  data.  In  the  stronger  solutions  the 


nickel  salt  shows  the  greater  conductivity,  but  at  higher  dilu- 
tion the  molecular  conductivity  and  the  temperature  coeffi- 
cients of  these  two  salts  are  almost  identical.  Conductivity 
in  these  cases  is  probably  somewhat  affected  by  hydrolysis. 

A  comparison  of  the  data  for  the  violet  and  green  varie- 
ties of  ammonium  chrome  alum  shows  that  in  the  more  con- 
centrated solutions  the  green  variety  has  much  higher  con- 
ductivity. At  higher  dilutions  the  reverse  is  true;  the  violet 
conducts  better  than  the  green  form.  The  same  general 
relation  is  shown  in  the  case  of  potassium  chrome  alum,  though 
fiv  for  the  green  variety  does  not  actually  fall  below  the  nv 
value  for  the  violet  form  at  the  highest  dilution  employed. 
This  relation  between  the  two  varieties  appears  in  Fig.  III. 


600 


500 


400 


300 


32  128       5/2  1024 


2048 

Concentration 


4036 


_,.     TTT  f X X X  Violet  variety 

Fig.  III.-Ammomum  chromium  sulphate  j_Q_Q_Q_   Green  Tariety 

The  violet  form  of  the  chromium  salts  is  transformed  into 
the  green  variety  by  heating  the  solid  salt  or  its  solution  for 
some  time  at  about  70°.  The  relation  between  the  two  forms 


32 

has  been  the  subject  of  many  investigations.  Monti1  ob- 
served that  the  change  was  accompanied  by  an  increase  in 
the  conductivity  of  the  solution.  Recoura,2  in  an  elaborate 
investigation,  explained  the  change  as  hydrolytic,  resulting 
in  the  formation  of  free  sulphuric  acid  and  a  basic  salt.  This 
conclusion  was  confirmed  by  Whitney.3  Jones  and  Mackay4 
showed  by  conductivity  measurements  that  the  transforma- 
tion was  continuous  as  the  temperature  rose  slowly  from 
37°. 5  to  90°. 

In  the  light  of  the  conclusions  of  these  workers,  the  explana- 
tion of  the  relative  conductivity  of  the  two  forms  of  ammonium 
chrome  alum  would  seem  to  be  that  the  green  modification, 
by  virtue  of  the  hydrolysis  caused  by  heating,  has  the  higher 
initial  conductivity,  but  when  diluted  it  is  incapable  of  further 
hydrolysis  to  the  same  extent  as  appears  to  occur  in  the  case 
of  the  normal  violet  variety. 

Salts  Studied  from  35°  to  65° 

Before  considering  in  detail  the  salts  studied  from  35°  to 
65°  some  general  relations  should  be  discussed.  It  was  found 
by  Jones  and  Ota5  and  by  Jones  and  Knight6  that  concen- 
trated solutions  of  certain  salts  in  water  often  show  abnormally 
great  depressions  of  the  freezing  point  of  the  solvent.  It  was 
also  shown  to  be  true  in  many  cases  that  the  molecular  lower- 
ing of  the  freezing  point  increased  from  a  certain  concentra- 
tion both  with  dilution  and  with  increased  concentration. 
The  subject  was  further  studied  by  Jones  and  Chambers7 
and  by  Jones  and  Getman.8  It  was  found  that  the  molecular 
conductivities  of  solutions  of  the  substances  which  showed  a 
minimum  in  the  value  of  the  molecular  lowering  were  per- 
fectly normal  at  all  concentrations. 

1  Z.  anorg.  Chem.,  12,  75  (1896). 

2  Ann.  chim.  phys.,  [7]  4,  494  (1895). 

3  Z.  physik.  Chem.,  20,  40  (1896). 
*  Am.  Chem.  J.,  19,  103  (1897). 

6  Ibid.,  22,  5  (1899). 
*Ibid.,  22,  110  (1899). 

7  Ibid.,  23,  89  (1900). 

«Z.  physik.  Chem.,  46,  244  (1903). 


33 

To  account  for  the  facts,  Jones1  offered  the  suggestion  that 
the  molecules  of  the  dissolved  substance  form  complex  com- 
pounds or  hydrates  with  a  portion  of  the  water,  thus  virtually 
increasing  the  concentration  of  the  solution.  The  freezing 
point  is  thus  abnormally  depressed.  It  was  also  pointed  out 
that  substances  which  give  these  abnormal  results  are  often 
hygroscopic  and  that,  when  dehydrated,  they  readily  com- 
bine with  water.  Jones  and  his  assistants  have  collected  a 
large  amount  of  evidence,2  by  several  independent  methods, 
which  supports  the  theory  of  hydration.  A  method3  was  de- 
veloped by  which  the  approximate  composition  of  the  hy- 
drates of  many  substances  was  calculated. 

It  was  pointed  out  by  Jones4  that  the  breaking  down  of  the 
hydrated  molecules,  or  of  the  hydrated  ions,  by  a  rise  in 
temperature  would  diminish  the  mass  of  the  ion  and  thus  in- 
crease the  conductivity.  The  more  complex  the  hydrates 
the  greater  would  be  the  change  in  hydration  and,  conse- 
quently, the  greater  the  change  in  conductivity.  Therefore 
"we  should  expect  to  find  those  ions  with  the  largest  hydrating 
power  having  the  largest  temperature  coefficients  of  conduc- 
tivity."* An  examination  of  the  experimental  results  of  Jones 
and  West6  led  to  the  following  conclusions : 

1.  The  temperature  coefficients  of  conductivity  of  aqueous 
solutions  of  electrolytes  are  greater,  the  greater    the  hydra- 
ting  power  of  the  electrolyte. 

2.  The  temperature  coefficients  of  conductivity  of  aqueous 
solutions  of  electrolytes  are  of  the  same  order  of  magnitude 
for  those  substances  having,  approximately,  the  same  hydra- 
ting  power. 

3 .  The  temperature  coefficients  of  conductivity,   for  any 
given  substance,  increase  with  the  dilution  of  the  solution, 
and  the  increase  is  greatest  for  those  substances  with  large 
hydrating  power.7 

1  Am.  Chem.  J.,  23,  103  (1900). 

2  See  Hydrates  in  Aqueous  Solution;  Carnegie  Institution  of  Washington,  Publica- 
tion No.  60. 

*  Ibid.,  pp.  28-145. 

4  Am.  Chem.  J.,  35,  445  (1906). 

5  Loc.  cit.,  p.  447. 

6  Am.  Chem.  J.,  34,  357  (1905). 

7  Ibid.,  35,  450  (1906). 


34 

Similar  results  were  obtained  by  Jones  and  Clover.1 
The  composition  of  the  hydrates  formed  by  some  of  the 
substances  which  were  brought  within  the  scope  of  this  inves- 
tigation has  been  approximately  determined  by  Jones2  and 
his  assistants.  In  general,  the  hydrating  power  may  be  taken 
as  roughly  proportional  to  the  amount  of  water  of  crystallization. 
The  substances  named  in  Table  LXXI  crystallize  with  little 
or  no  water,  and  have  slight  hydrating  power.  They  are 
seen  to  have  small  temperature  coefficients  of  conductivity. 
The  substances  named  in  Table  LXXII  have  large  hydrating 
power  and  also  have  large  temperature  coefficients  of  conduc- 
tivity. 

Table  LXXI. — Substances  with  Slight  Hydrating  Power 

Temperature  coefficients  in  conductivity  units 


V  V  Temp,  range 

KCNS                                   4  2.17  2048  3.01  35°-50° 

KC2H3O2                                4  2.08  2048  2.29  35°-50° 

Ca(OOCH)2                           4  2.15  2048  4.02  25°-35° 

Zn(C2H302),                          4  0.70  2048  3.69  25°-350 

Pb(C2H302)2.3H20                4  0.49  2048  3.23  25°-350 

CaCrO4.2H2O                        8  1.96  2048  5.00  25°-35° 

Table  LXXII. — Substances  with  Large  Hydrating  Power 

Temperature  coefficients  in  conductivity  units 

V  V  Temp,  range 

Ni(N03)2.6H20                     4  3.44  2048  6.05  35°-50° 

CaCl2.6H20                            4  3.24  2048  5-59  35°^5O0 

MgCl2.6H20                           4  3.21  2048  5.60  35°-5°° 

Zn(NO3)2.6H20                    4  2.46  2048  4.78  250-35° 

FeCl3.6H20                            4  3.68  2048  14.7  35°-5O° 

HNa2PO4.i2H2O                   8  2.82  2048  4.65  35°-5O° 

H2KP04                                 8  5.41  2048  8.56  35°-50° 

Na2B407.5H20                     16  2.77  2048  4  73  35°-5O° 


The  values  used  in  these  tables  are  not  strictly  compara- 
ble, since  the  concentrations  and  the  ranges  of  temperatures 
at  which  the  temperature  coefficients  were  determined  are 
not  the  same  throughout,  but  the  agreement  is  sufficiently 
close  to  warrant  their  use  in  showing  the  general  relations. 

*  Am.  Chem.  J.,  43,  215  (1906). 

2  Hydrates  in  Aqueous  Solution;  Carnegie  Institution  of  Washington,  No.  SO. 


35 

My  results  confirm  the  conclusion  of  Jones  cited  above,  and 
are  in  perfect  accord  with  the  theory  of  hydration  advanced 
by  him. 

The  sulphates  which  I  have  studied  in  this  investigation 
are  omitted  from  Tables  LXXI  and  LXXII,  because,  as  shown 
by  Jones  and  his  coworkers,1  the  sulphates  usually  show  ab- 
normal results.  In  general,  sulphates  have  very  small  tem- 
perature coefficients  of  conductivity,  and  appear  to  have 
small  hydra  ting  power  in  solution.  There  is  evidence  that 
some  sulphates,  at  least,  are  polymerized  in  concentrated 
solutions. 

Sodium  tetraborate  gives  normal  conductivity  results  at 
35°,  but  at  higher  temperatures  the  increase  in  conductivity 
with  dilution  is  exceptionally  rapid.  The  salt  also  has  large 
temperature  coefficients  of  conductivity,  and  is  undoubtedly 
hydrated  in  solution.  Boric  acid  being  little  dissociated  and, 
therefore,  a  weak  acid,  the  sodium  salt  would  certainly  undergo 
hydrolysis.  By  assuming  both  hydration  and  hydrolysis  to 
take  place,  the  behavior  of  the  salt  is  easily  accounted  for. 
At  the  lower  temperatures  the  hydrolysis,  due  to  increasing 
dilution,  is  balanced  by  the  increasing  complexity  of  the 
fairly  stable  hydrates.  As  the  temperature  rises  the  hydrates 
break  down,  while  hydrolysis  continues  unchecked  so  that 
the  conductivity  increases  rapidly. 

Calcium  and  magnesium  chlorides  give  almost  identical 
results,  except  that  the  molecular  conductivity  of  the  cal- 
cium salt  is  about  ten  conductivity  units  above  that  of  magne- 
sium chloride.  The  latter  salt  shows  greater  increase  in  the 
value  of  fiv  with  dilution  at  56°,  which  accords  with  its  greater 
hydration,  as  shown  by  Jones  and  Bassett.2 

Nickel  nitrate  also  shows  large  temperature  coefficients. 
It  is  known3  to  possess  marked  power  of  hydration. 

The  conductivity  data  for  the  sulphates  of  nickel,  cobalt, 
copper,  and  manganese  are  remarkably  similar  in  every  re- 

1  Hydrates  in  Aqueous  Solution;  Carnegie  Institution  of  Washington,  Publica- 
tion No.  60,  pp.  80,  136,  148. 

2  Am.  Chem.  J.,  33,  555  (1905). 

3  Jones:    Hydrates   in   Aqueous   Solution;   Carnegie   Institution   of   Washington, 
Publication  No.  60,  p.  78. 


36 

spect.  There  is  little  indication  of  an  approach  to  p.^  at  the 
highest  dilution  employed.  The  temperature  coefficients  are 
not  large  in  concentrated  solutions,  but  increase  rapidly  with 
dilution.  This  behavior  is  probably  due,  in  part  at  least,  to 
the  polymerization  of  the  sulphates  in  concentrated  solu- 
tions. 

The  molecular  conductivity  of  the  quaternary  electrolytes, 
chromium  sulphate  and  ferric  chloride,  increases  very  rapidly 
with  dilution  and  also,  in  dilute  solutions,  with  rise  in  tem- 
perature. Hydrolysis  undoubtedly  plays  a  prominent  part. 
In  the  case  of  ferric  chloride  distinct  precipitation,  due  to 
hydrolysis,  occurred  at  65°  in  the  N/8  and  N/32  solutions. 
The  conductivity  curve  of  this  salt  is  interesting  (Fig.  IV). 

65°       5o°        35° 


1024 


512 

128 
32 


idoo   I5OO   I4OO   I3OO   I2OO   IIOO   IOOO    QOO    800  7OO  6OO  5OO  400   300    200 

Conductivity 
Fig.  IV. — Ferric  chloride 

The  abrupt  bend  in  the  curve  for  50°  and  65°  at  the  N/5I2 
concentration  indicates  that  the  cause  of  the  increasing  con- 
ductivity— presumably  hydrolysis — is  rapidly  becoming  less 
effective.  It  would  seem  that  under  these  conditions  of  tem- 
perature and  dilution  the  hydrolysis  of  the  salt  is  very 
great. 

The  ammonium  and  potassium  alums  were  studied  through 
both  ranges  of  temperature  (o°-35°  and  35°-65°),  and  the 


37 


values  of  pv  recorded  for  35°  were  deduced  from  all  the  read- 
ings made  at  this  temperature.     Fig.  V  shows  the  conduc- 


Conductivity 


tivity-temperature   curves  for  potassium   alum   through   the 
entire  range  of  temperature.     In  strong  solutions,  at  ordinary 


temperatures,  molecular  conductivity  is  nearly  a  linear  func- 
tion of  temperature ;  but  at  greater  dilutions  the  curve  in  para- 
bolic.1 All  of  the  salts  studied  in  this  investigation  yield 
conductivity-temperature  curves  of  this  same  general  charac- 
ter. 

The  condition  of  double  salts,  when  in  solution,  presents  a 
problem  of  interest.  Investigators  have  sought  for  evidence 
which  would  decide  whether  such  salts,  when  dissolved,  break 
down  into  their  constituent  salts,  which  then  dissociate  in  the 
usual  way;  or  whether  they  ionize  to  some  extent  as  salts  of 
complex  acids.  Four  investigations2  bearing  on  the  general 
problem  have  been  carried  out  in  this  laboratory.  Jones  and 
Mackay  compared  the  conductivity  of  certain  alums  with  the 
sum  of  the  conductivities  of  the  constituent  salts.  They 
found  the  conductivity  of  the  alums  in  dilute  solutions  to  be 
almost  the  same  as  the  sum  of  the  conductivities  of  the  com- 
ponents. In  concentrated  solutions  the  alums  were  found  to 
have  a  conductivity  less  than  the  sum  of  the  conductivities  of 
the  components,  and  the  difference  increased  with  the  concen- 
tration. The  difference  was  greater  than  that  observed  when 
mixtures  of  sulphates  incapable  of  forming  double  salts  were 
compared.  Similar  methods  were  used  by  the  other  workers. 
The  general  conclusion  from  these  researches  was  that  the 
double  salts  in  moderately  concentrated  solutions  are  not 
wholly  broken  down  into  the  simple  salts. 

In  these  investigations  the  conductivities  were  measured 
at  25°.  As  we  now  have  at  hand  conductivity  data  over  a 
considerable  range  in  temperature,  it  appears  to  be  of  interest 
to  apply  the  method  of  Jones  and  Mackay  at  other  tempera- 
tures. 

The  following  is  the  table  of  Jones  and  Mackay3  giving  the 
comparisons  for  potassium  alum  at  25°: 

1  Jones  and  Jacobson:     Am.  Chem.  J.,  40,  402    (1908).     White  and  Jones:   Ibid.. 
44,  199  (1910). 

2  Jones  and  Mackay:  Ibid.,  19,  83  (1897).     Jones  and  Ota:  Ibid.,  22,  5  (1899). 
Jones  and  Knight:  Ibid.,  22,   110  (1899).     Jones  and  Caldwell:  Ibid.,  25,  349  (1901). 

3  Ibid..  34,  357  (1905). 


39 
Table  LXXIII. — Potassium  Alum,  25°  (Jones  and  Mackay) 


V 

KaSO, 

A12(S04)3 

Sum/2 

KA1SO4 

Diff. 
Per  cent. 

5 

172.7 

108.0 

140.3 

133-9 

—4-5 

8 

183.3 

124.2 

153-7 

149.2 

—3.0 

20 

205.1 

I58.I 

181.6 

178.3 

—1.7 

40 

220.3 

185.7 

203.0 

202.5 

O.2 

200 

252.4 

290.4 

271.4 

269.0 

—  0.8 

4OO 

262  .2 

342.6 

302.4 

305-2 

+  0.9 

This  may  be  compared  with  Table  LXXIV,  which  gives  the 
corresponding  relations  at  o°,  35°,  and  65°.  The  values  of 
the  conductivity  of  aluminum  sulphate  were  kindly  furnished 
by  Miss  L.  G.  Winston.  The  conductivity  values  of  potassium 
sulphate  are  taken  from  the  work  of  Jones  and  West.1 

Table  LX XIV .—Potassium  Alum 


V 

K2SO 

A12(S04)3 

Sum/2 

KA1SO4 

Diff, 

Diff. 
Per  cent. 

8 

IOI  . 

9 

65 

2 

83 

.6 

78. 

9 

—4- 

7 

—5-6 

32 

117. 

9 

89 

•5 

103 

•7 

IOI 

.2 

2  . 

5 

—2.4 

128 

131 

9 

121 

.8 

126 

•9 

127 

.6 

+  0. 

7 

+  0.5 

512 

142. 

7 

164 

.  i 

153 

•4 

158 

.8 

+  5- 

4 

+  3-5 

35° 

8 

220. 

3 

137 

.2 

I78 

.8 

I65 

•3 

-13- 

5 

—7-5 

32 

259- 

7 

I97 

.  I 

228 

•4 

215 

•7 

—  12  . 

7 

—5-5 

128 

296. 

9 

274 

.  I 

285 

•5 

283 

•  7 

-  I  . 

8 

—  0.6 

512 

3I9- 

6 

388 

.  I 

353 

9 

358 

3 

+  4- 

4 

+  1.2 

65° 

8 

332- 

8 

188 

•4 

260.6 

240 

,6 

—  20. 

o 

—7-7 

32 

400. 

0 

264 

.6 

332 

•3 

317 

4 

—14. 

9 

—4-5 

218 

456. 

2 

387 

.6 

421 

•9 

426 

.2 

+  4- 

3 

1  .0 

512 

500. 

7 

581 

.6 

54i 

.  i 

557 

.  I 

+  16. 

0 

+  2.9 

My  values  for  "difference"  in  per  cent,  are  of  the  same 
order  of  magnitude  as  those  obtained  by  Jones  and  Mackay, 
and  confirm  their  conclusions.  It  is  noticeable  that  the  per- 
centage differences  are  nearly  the  same  at  the  various  tem- 
peratures. This  may  be  regarded  as  evidence  that  the  break- 
ing down  of  potassium  alum  in  solution  is  little  affected  by 
temperature,  which,  from  other  evidence,  is  known  to  be 
true  of  dissociation  in  general. 

i  Am.  Chem.  J.,  84,  357  (1905). 


40 

In  Table  LXXV,  from  the  work  of  Jones  and  Caldwell,1 
the  conductivity  of  the  double  salt,  potassium  nickel  sulphate, 
is  compared  with  the  sum  of  the  conductivities  of  the  com- 
ponents, all  measurements  being  made  at  25°.  Table  LXXVI 
shows  the  same  relations  for  this  salt  at  o°  and  35°.  The 
values  for  the  conductivity  of  nickel  sulphate  given  in  Table 
LXXVI  are  taken  from  the  work  of  Jones  and  Jacobson.2 

Table  LXXV. —Potassium  Nickel  Sulphate,  25°  (Jones  and 

Caldwell) 


Diff. 

V 

K2S04 

NiS04 

Sum 

K2Ni(S04)2           Diff. 

Per  cent. 

8 

182.4 

77-9 

260.3 

219-5 

—40.8 

-I5.6 

40 

22O.3 

109.0 

329-3 

291  .6 

—37-7 

—II.4 

80 

237-9 

122.8 

360.7 

323-7 

—37-0 

—10.3 

400 

262  .2 

173-1 

435-3 

400.2 

—35-1 

—  8.0 

800 

273.0 

194.8 

467.8 

438.0 

—  29.0 

—  6.2 

v 
8 

32 

128 

512 

1024 

8 

32 

128 

512 

1024 


Table  LXXVI.— Potassium  Nickel  Sulphate 


NiS04 
40.4 

54-8 

73-9 

93-i 

100.4 

90.9 
123.0 
168.4 

213-5 
234.6 


IOI  .9 
II7.9 

I3I-9 
142.7 

145-0 

219.8 
256.9 

291  .o 

318.4 
325-0 


0° 

Sum 

K2Ni(S04)2 

Diff. 

H2.3 

122  .6 

—19.7 

172.7 

155-4 

—17-3 

205.8 

187.5 

—I8.3 

235-8 

219.6 

—  16.2 

245-4 

235-5 

—   9.9 

35° 

310.7 

268.3 

—42.4 

379-9 

339-7 

4O.2 

459-4 

414.1 

—45-3 

531-9 

490.7 

—41.2 

559-6 

527-1 

—32-5 

Diff. 
Per  cent. 

-I3.8 
— IO.O 
-8.9 

9 
.o 


—13-7 
— 10.6 

—  9-8 

—  7-7 
-5-8 


The  percentage  "differences"  at  o°  and  35°  agree  closely 
with  those  found  by  Jones  and  Caldwell  at  25°,  showing  that 
the  relations  which  they  established  as  holding  at  25°  are  also 
true  at  higher  and  lower  temperatures.  My  results  also  ac- 
cord with  the  general  law  that  dissociation  is  nearly  independ- 
ent of  temperature. 


1  Am.  Chem.  J.,  25,  349  (1901). 

2  Ibid.,  40,  390  (1908). 


SUMMARY 

1.  The  molecular  conductivities  of  fifteen  inorganic  salts 
from  o°  to  35°,  and  of  sixteen  inorganic  salts  from  35°  to  65°, 
were  measured  by  the  Kohlrausch  method.     The  tempera- 
ture coefficients  of   conductivity,  both  in  conductivity   units 
and  in  percentages,  were  calculated  for  these  salts  through  the 
ranges  of  temperature  above  stated.     The  percentage  disso- 
ciations were  also  calculated  in  all  cases  where  the  data  were 
sufficient. 

2.  Jones  and   his   coworkers1  have  shown  that  the  ions  of 
an  electrolyte  are  hydra  ted  in  aqueous  solutions,  and  that  the 
complexes  break  down  with  rise  in  temperature,  thus  increas- 
ing  the   conductivity.     If   this   is   true,   substances   of  large 
hydrating  power  should  have  large  temperature  coefficients 
of  conductivity.     Jones2  showed  this  to  be  true  for  the  sub- 
stances studied  by  Jones  and  West.3    The  substances  which 
I   have   studied   show  the  same  relations  and  my  results  are 
in  perfect  accord  with  the  theory  of  hydration. 

3.  Hydrolysis  is  evidently  a  frequent  cause  of  abnormally 
great  conductivity.     It  is  increased  both  by  dilution  and  by 
rise  in  temperature. 

4.  Another  probable  cause  of  abnormally  rapid  increase  in 
conductivity  is  decrease  in  polymerization.     There  is  evidence 
that  sulphates  are  polymerized  in  concentrated  solutions. 

5.  Observers  have  found  an  increase  in  the  conductivity 
of  a  solution  of  a  chromium  salt  when  it  is  changed  from  the 
violet  to  the  green  variety.      My  results  show  that  while  the 
conductivity   is    increased   in  concentrated  solutions   by  this 
change,  the  increase  is  relatively    less    at   higher    dilutions. 
The  conductivity  of  the  green  variety  may  even  fall  below 
that  of  the  violet  variety.     This  would  appear  to  show  that 
the  green  variety  is  not  as  susceptible  to  hydrolysis  by  dilu- 
tion as  is  the  normal  violet  form. 

1  Hydates  in  Aqueous  Solution;  Carnegie  Institution  of  Washington,  Publication 
No  60. 

2  Am.  Chem.  J.,  35,  445  (1906). 

3  Ibid.,  34,  357  (1905). 


42 

6.  Jones  and  his   coworkers1  found  that  the  conductivities 
of  alums  and  other  double  salts  were  less  than  the  sum  of  the 
conductivities  of  the  constituent  salts.     They  inferred  that 
double  salts  exist  as    such  to    some  extent  in  concentrated 
solutions.     Their  work    was    done    at    25°.     I   have  made 
similar  comparisons  at  other  temperatures,  and  find  that  the 
relations  pointed  out  by  them  as  holding  at  25°  also  manifest 
themselves  from  o°  to  65°.     In  addition,  my  results  show 
that  the  breaking  down  or  dissociation  of  double  salts,  like 
dissociation  in  general,  is  little  affected  by  temperature. 

The   following   general   relations,    established   by   previous 
investigators,  are  true  of  the  salts  which  I  have  studied: 

7.  The   temperature-conductivity    curves   for   concentrated 
solutions   are   nearly   straight  lines;   at  higher  dilutions   the 
curves  are  often  parabolic. 

8.  The   percentage   temperature   coefficients   increase   with 
dilution,   but  decrease  with   temperature.     Temperature   co- 
efficients in  conductivity  units  increase  with  dilution. 

9.  Dissociation    decreases    with    temperature.     Four    salts 
among  those  studied  seem  to  be  exceptions  to  the  rule. 

*  Jones  and  Mackay:  Am.  Chem.  J.,  19,  83  (1897).  Jones  and  Ota:  Ibid.,  22,  5 
(1899).  Jones  and  Knight:  Ibid.,  22,  110  (1899).  Jones  and  Caldwell:  Ibid.,  25, 
349  (1901). 


BIOGRAPHY. 

Henry  Hallock  Hosford  was  born  July  12,  1859,  at  Hudson, 
Ohio.  He  prepared  for  college  at  Hudson  and  entered  West- 
ern Reserve  College,  graduating  with  the  degree  of  Bachelor  of 
Arts  in  1880.  Three  years  later  he  received  the  degree  of 
Master  of  Arts  from  his  Alma  Mater. 

After  teaching  for  several  years  in  Western  Reserve  Academy, 
Mr.  Hosford  became  professor  of  chemistry  in  Doane  College, 
Crete,  Nebraska,  which  position  he  still  occupies.  In  1892  he 
married  Jennie  Chamberlain,  daughter  of  Dr.  W.  I.  Chamber- 
lain, of  Hudson,  Ohio.  They  have  four  children. 

In  October,  1909,  Mr.  Hosford  entered  Johns  Hopkins 
University  as  a  graduate  student  in  Chemistry  with  Physical 
Chemistry  and  Physics  as  his  subordinate  subjects. 


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w  n-""*4 

MAY  12  v. . 
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--L-349RF 


JUN9    1960   |Q 


LD  21-50m-l,'33 


GAYLORD   BROS. 

MAKERS 

SYRACUSF.,  -  N.Y. 

PAT.  JAN.  21,  I30B 


